Changes in the direction of induced aniseikonic slant as a function of distance.

Abstract The nature of the binocular slant and shape distortions induced by 90 degree magnification of one retinal image was investigated as a function of stimulus distance. At close distances both distortions were in accordance with geometric prediction. At distances above 126 cm the slant distortion was reported to be in the reverse direction from prediction in a significantly high proportion of cases, whereas the shape distortion disappeared. It is proposed that “reverse slants” result from the interpretation of the shape distortion as a perspective and that perspective cues to slant are more relied on at greater distances.